Autonomous vehicles, such as vehicles that do not require a human driver, can be used to aid in the transport of passengers or items from one location to another. Such vehicles may operate in a fully autonomous mode where passengers may provide some initial input, such as a destination, and the vehicle maneuvers itself to that destination.
Typically when vehicles that drive fully autonomously or in an autonomous mode encounter other vehicles or objects on a roadway, these vehicles are programmed to operate as safely as possible. In other words, these vehicles tend to “err” on the side of being less assertive when pulling out in front of other vehicles to make turns, etc. However, in many situations, this preference for safety and less assertive behaviors can lead to delays in operation and annoyances to passengers—especially those in which vehicle or pedestrian congestion is relatively high. At the same time, making more assertive maneuvers, such as pulling out in front of another vehicle, which would require the other vehicle to slow down, change direction, or make some other responsive maneuver, is inherently dangerous. As an example, assuming the other vehicle is controlled by a human driver, if the vehicle in the autonomous mode pulls in front of the other vehicle, the human driver may not react soon enough to slow the other vehicle down, change direction, etc. in order to avoid a collision. Thus, there is a delicate balance between increasing the assertive nature of these autonomous vehicles and compromising on safety.